Need color tips for snow skiing video

dibbkd wrote on 2/8/2012, 7:19 PM
So I used my GoPro HD camera on my last ski trip, had a great time and got quite a bit of footage. Was looking for some tips on color balancing for snow white scenes. There's no way to do any color balancing on the GoPro that I know of, so everything has to be done in post.

Edit: Here's a link to what I've done so far using the Color Corrector and Color Curves:

http://vimeo.com/36610684Skiing video[/link]

Comments

MTuggy wrote on 2/8/2012, 7:43 PM
I have done a lot of this kind of work. Should be take this off line?

Mike
dibbkd wrote on 2/8/2012, 8:26 PM
I'd love to hear any tips you had, did you want me to call or email you? (when you said take it offline)
rs170a wrote on 2/8/2012, 8:34 PM
My vote is to keep it online so that everyone can benefit from the advice, not to mention the fact that it will be available for future users doing a search on the topic.

Mike
[r]Evolution wrote on 2/9/2012, 4:47 AM
At least post the Meat & Potatoes of the discussion/findings.
MikeyDH wrote on 2/9/2012, 8:30 AM
I'd have to agree with those who would like to learn from this forum. What iis the point of even coming here if everything turns into a secret?
TeetimeNC wrote on 2/9/2012, 9:26 AM
Kevin, I'll contribute a tip. Camera exposure is based on neutral gray. So, without compensation snow will look gray (as will a black cat). When shooting a snow scene you have to increase exposure over what the meter calls for.

Then in vegas, use the color corrector to white balance it. Since I will be seeing you tonight at the Raleigh Vegas User Group we can explore further there. Bring some footage.

/jerry
MTuggy wrote on 2/9/2012, 10:20 AM
OK, I'll put up a message this afternoon with the various methods I've used to clean up snow footage. My real job has me tied up until then. Sorry, not trying to be elusive, just need the time to lay it out right for you.

Mike
Andy_L wrote on 2/9/2012, 10:40 AM
Are you talking about color as in color tint/cast, or as in levels (or both)?

MTuggy wrote on 2/9/2012, 2:01 PM
There are two conditions you run in to when shooting in snow - the blown out sunny day or the cloudy day. I'll describe what I do for each.

The summer snow day is problematic if your camera (like the GoPro) doens't have neutral density filter capability. I did purchase a lens filter for the GoPro for about $15 (a simple ND Film shaped to cover the lens in the case) to darken summer snow footage. This hasn't been necessary in the winter since the light is much less intense.

OK, now about post processing:
Cloudy snow footage:
Before the Sony WB Fx was available, I'd use Sony HSL adjust much of time. Usually dialing up the luminescence to about 1.2-1.3 and boosting the saturation to about 1.07 to 1.1 would eliminate the grey appearance of the snow enhance the colors to a more realistic appearance on the output video. In this process I have my histogram and videoscope window open to keep the brightness levels clamped between 10-90% and the color well centered in the scope.

Now with the WB plugin, I first select the white color in a somewhat lighter area of snow in the video clip. You can use just with the Brightness slider to boost the greys to whites (usually 1.1 or so). The Amount of Correction slider is more subjective - the video can look too blue very easily so usually I move it left to bring in more red/yellow to warm the snow lighting a bit.

On bright day footage, using Sony WB and then Sony Levels to clamp the brightness and adjust the output is what I use now. Use the WB correction slider to adjust color to the warmth you want, though the GoPro had good warm colors at baseline. Blown out footage is tough - I've had to desaturate that footage to eliminate odd color artifacts that are often present (a greenish hue on sunny days, and a pink hue on white out days)- better to filter the camera on those days.

Hope that helps. - use your video scopes and histogram tools either way.

Mike


riredale wrote on 2/9/2012, 2:52 PM
Whatever you do, don't make yellow snow. That will gross people out.
MikeyDH wrote on 2/9/2012, 8:37 PM
Thanks for your advice, Mike! It is truly appreciated....;^)
dibbkd wrote on 2/9/2012, 9:31 PM
Thanks Jerry and Mike for the tips, I'll work on it some this weekend and post the results and welcome anymore advice.

@Andy_L, my main concern was some of the scenes are super bright white snow and others the snow is darker in the shadows and was just trying to kind of even it out to look more consistent. And also wanted general help with what to do with so much white in the footage.
Andy_L wrote on 2/10/2012, 7:28 PM
You're just kind of at the mercy of these cameras when it comes to exposure. I've used a Contour extensively, and just got a GoPro 2. With the 1st Gen GP and Contour, overexposed snow was a big problem. Some scenes would have basically 50-60% or more of the screen completely blown out (and unrecoverable).

Trying to make that match shadowy or partly sunny footage was an exercise in futility. ND filters can tame the highlights, but all of the ND systems are awkward to use, few include high quality filters, and with chip sizes this small, they tend to come with big image degradation issues (esp. an issue with the Contour).

It looks to me like the GP2 is doing a better job keeping detail in bright sunlit snow, and Contour says their new flagship is better at highlight detail also, so upgrading (if you're using one of the earlier models) might be the simplest option, if you can.

I would also say that the 'look' of the Contour/GoPro helmet cams is by now well established in people's minds, including the crazy fisheye distortion, the oversaturated colors, the granular texture, the blurry corners, the shutter roll, and the totally blown highlights. What looks terrible to the videographer's eye is pretty much ingrained as "helmet cam" footage in the public's eye, and therefore perfectly acceptable.

Don't let that stop you from playing around with the Sony levels plugin to see what you can accomplish (and try per-channel levels for color grading), but remember that the thrill of these cameras is their immersive, POV effect. Beware trying to chase the IQ of better HD cams - you can drive yourself batty!



dibbkd wrote on 2/11/2012, 6:27 PM
Here's a link to what I've done so far using the Color Corrector and Color Curves:

http://vimeo.com/36610684Skiing video[/link]
TeetimeNC wrote on 2/12/2012, 6:21 AM
Kevin, I like cuts and am envious re the skiing. Maybe we can ski together some time ;-).

On my monitor (which I think is properly calibrated) the snow looks to have too much red in it. I'll take a look at if on my other PC and report back later.

EDIT: I took a screen capture and checked a random snow spot in Photoshop and got the following read:

Red: 206
Green: 204
Blue: 200

I think it needs a bit more blue. Let's see what other's think - my monitor may need recalibrating if it looks correct for others.

/jerry
farss wrote on 2/12/2012, 4:03 PM
"You're just kind of at the mercy of these cameras when it comes to exposure."

Oddly enough my el cheapo Crocolis camera does offer a reasonable amount of exposure control, yeah for that. The PQ is not as good as the latest GoPro camera so it's a bit of toss up as to which is better although given that one can buy two "Crocs" for one GoPro it could still be a winner.

Bob.
dibbkd wrote on 2/12/2012, 5:10 PM
Jerry - when you say "more blue", would that be in the high, mid, or low part of the color corrector? Or just a little of all of them?

Also, I want to do a split-screen where half the screen is "raw" and the other half is color corrected, just to show the difference. Would that be a mask? I'm having a brain freeze on how to do that.

And yeah, we'll have to plan something next season to find some slopes, sounds fun and I'm sure we'd get some great video!
TeetimeNC wrote on 2/13/2012, 10:48 AM
Add some blue in the mid and high.

Re the split screen, put "before" on one track, "after" below it on another track and use track motion on each track to set up each window.

I've got my skis waxed and ready to go!

/jerry